FAMILY ICTERIDAE 



345 



Description. — Length, male 412-442 mm, female 319-340 mm. Adult 

 (sexes alike except for size), entirely black except for rump, lower 

 abdomen, and upper and undertail coverts, which are chestnut, and for 

 tail, in which all but central pair of rectrices are bright yellow; central 

 pair of rectrices black, shorter than others. 



Immature, similar, but black and chestnut areas duller, sometimes 

 with brown edging; bill yellowish brown or brownish white. 



A female collected at El Real, Darien, on January 23, 1964, had the 

 iris dark gray; bill ivory, slightly more yellowish on basal third; tarsus, 

 toes, and claws black. A male taken at Alanje, Chiriqui, on March 12, 

 1960, had the iris bright blue. 



Measurements. — Males (10 from Panama and Colombia), wing 

 196.0-236.0 (213.7), tail 170.2-207.0 (188.0), culmen from base 57.9- 

 64.8 (60.4), tarsus 49.3-51.4 (50.6) mm. 



Females (10 from Panama), wing 160.0-179.8 (168.6), tail 137.1- 

 159.0 (151.6), culmen from base 46.0-49.3 (47.7), tarsus 39.0-43.3 

 (41.3) mm. 



Resident. Locally common in forest borders, second-growth wood- 

 lands, and clearings in the lowlands of the Pacific slope from western 

 Chiriqui (Buguba, Divala, Concepcion), where it is scarce with few 

 recent reports, to the Colombian boundary in Darien, including the 

 Azuero Peninsula (south to Tonosi and Pedasi, Los Santos), ranging 

 at least locally to the lower edge of the Subtropical Zone (above El 

 Valle, Code; Cana, Darien) . In March 1981 it was the only oropendola 

 present at Cana; here it was abundant and nesting (Ridgely, in litt.). 

 On the Caribbean side it is found in scattered colonies along the Rio 

 Indio, from above the mouth near Chilar, Colon to El Uracillo, Code, 

 and in the Canal Zone and vicinity (Ridgely, 1976, p. 307). This 

 species is much commoner in Darien than it is further west, and al- 

 though unrecorded from San Bias, will probably be found there as it is 

 common in adjacent northern Colombia. In the Bayano Valley of 

 eastern Province of Panama, however, it is still outnumbered by P. 

 wagleri. Other races of Psarocolius decumanus are found in Colombia 

 east of the Andes, south through Ecuador, Peru, and Bolivia to north- 

 ern Argentina and east to the Guianas, Trinidad and Tobago, and much 

 of Brazil. 



The habits of this species are very like those of other oropendolas. 

 Its calls are similar in quality to the vocalizations of P. wagleri, al- 

 though they seem less varied and most are lower in pitch. It nests in 

 colonies, often in smallish Cecropia trees, sometimes in association with 

 P. wagleri or with Yellow-rumped Caciques (Cacicus cela) . A colony 



